JPS63301836A - Purification of crude isopropyl alcohol - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for purifying crude isopropyl alcohol.

It is well known that isopropyl alcohol (IPA) is commonly produced by a process involving the hydration of propylene. Hydration can occur directly or indirectly. In direct hydration, propylene reacts catalytically with water. Suitable catalysts for this purpose are known to include cation exchange resins, phosphoric acid, silicon tungstate compounds, and the like.

An indirect hydration process of particular interest in the application of the present invention consists of reacting propylene with sulfuric acid to form propane sulfate and then hydrolyzing the sulfate to the desired IPA.

The crude products obtained from the propylene hydration process generally contain not only the desired IPA, but also diisopropane ethers, polymers (e.g. propylene trimer).

(tetramer, trimer, etc.), and water.

Organosulfur derivatives have also been found in the products of indirect hydration processes. In a typical operation, the crude product is 6
0% by weight IPA, 6% by weight diisopropyl ether, up to 0.5% by weight polymers and sulfur derivatives, small amounts of acetone and propane.

and residual water.

In common practice, crude IPA from indirect propylene hydration is usually purified or worked up to IPA by removing diisopropyl ether and other impurities by distillation and/or extractive distillation.

The objective of the present invention is to provide a crude IPA finish.
finish-4ng). In one aspect, another object of the present invention is to reduce the operational difficulties and expense associated with prior art applications of coarse IPA finishing. Conventional distillation means are extremely expensive due to the equipment required and the energy required to operate this equipment, e.g. to evaporate not only the organic ether and IPA products but also the large amounts of water that accompany the IPA during purification. become. For example, one typical conventional means of purifying crude IPA is to send the crude product stream from propylene hydration to a multi-tray extractive distillation column and distill off large amounts of diisopropyl ether and other impurities using a water extractant. and leaving a bottoms containing about 15% IPA in water. This IPA solution is then subjected to multistage distillation to recover an overhead distillate containing primarily an azeotrope of IPA and water. Then,
The IP^/aqueous solution is azeotropically distilled with an added azeotropic agent for dehydration (eg purified isopropyl ether). 06-01
□The azeotropic distillation effluent, in which heavy components including polymer and diisopropyl ether remain, is further fed to a multi-stage distillation.

In another aspect, another object of the present invention is to effectively remove certain impurities from crude IPA.

Of particular interest in this regard is the enhancement of the performance of purification processes that remove organosulfur derivatives from the products of indirect hydration processes. Even when present in very small amounts, sulfur derivatives often impart a highly undesirable odor to purified IPA. Difficulties associated with sulfur removal arise in products without the stringent safety specifications required for IPA for many end uses, such as when used in the preparation of cosmetics and pharmaceuticals.

In the crude isopropyl alcohol purification process of the present invention for removing diisopropyl ether monopolymer and/or sulfur-containing impurities from the crude isopropyl ether product of propylene hydration, the following steps: (a) Crude IPA is purified in a subsequent process step ( f) the recycle stream from step (a), and optionally mixed with added water to obtain a mixture containing from 73 to 83% by weight; (b) in a first phase separation step, the mixture from step (a); diisopropyl
phase separation into a first upper phase rich in ether (non-polar) and a first lower phase rich in IPA and water (polar); (c) removing the first upper phase from the process; and (d) removing the first lower phase. with added diisopropyl ether to give 10-21% by weight of IPA, 1-3 based on the total weight of the product mixture.
(e) in a second phase separation step, the mixture from step (d) is separated into a diisopropyl ether-enriched second upper phase (non-polar ) and a second lower phase rich in IPA and water (polar), (“) recycling the second upper phase to step (a) as a recycle liquid to be mixed with the crude IPA, and (g) The second lower phase is characterized in that it is recovered as a purified IPA product.

In practice, the sequential phase separation in the present invention converts most of the diisopropyl ether of the crude rpΔ into such crude IP.
It acts to remove from A. Most importantly, the means for separating the ether from the IPA serves to concentrate the bulk polymeric and sulfur-containing impurities of the crude PA in the removed ether. The process concentrates these impurities into a stripped ether-rich product and achieves significant purification of the IPA by means other than distillation.

IP recovered from the process as a result of the practice of the present invention
A. The aqueous solution is extremely refined and can produce a high purity IPA product. The invention also provides savings in equipment and energy costs and/or
or the ability to produce high quality, particularly low odor, IPA products.

In its broadest sense, the process of the present invention provides a method for removing diisopropyl ether and polymeric impurities.
It is applicable to the purification of any crude IPA product containing various urities. The present invention specifically describes the use of oxidation agents made by indirect hydration of propylene, which are
) It is particularly advantageous when applied to the treatment of crude fPA containing sulfur compounds. However, the invention can also be very advantageously applied to the purification of directly hydrated IPA products.

The present invention is meant primarily to apply to the crude product of the hydration process. A typical crude IPA from ordinary propylene hydration includes, for example, about 40-70% IPA, about 1-10% diisopropyl ether, about 0.1% by weight IPA, about 1-10% diisopropyl ether, about 0.1
~2% by weight of polymer and/or sulfur-containing impurities, a small amount (e.g. 0.1-1% by weight) of acetone and the balance (
For example, it contains 20 to 55% by weight of water. Examples of polymer impurities include propylene double polymers, triple polymers, tetrapolymers, terpolymers, etc., adducts of propylene, and polymers of propylene and impurities found in other components introduced into the hydration reaction. . Sulfur impurities in the product of indirect propylene hydration may be found significantly in conjunction with dark polymer species. The relative proportions of the various components of the crude IPA will vary somewhat depending on factors such as the source of the propylene material and the nature of the hydration process. Approximately 5
5-60% by weight IPA, about 5% by weight diisopropyl ether, about 0.5% by weight polymer and/or sulfur-containing impurities.

A crude IPA product containing about 0.5% by weight acetone and about 40% by weight water is a very typical crude rPA product.

Similarly, the present invention provides one or more prepurification steps and also a significant amount of diisopropyl ether (e.g., at least about 1% by weight, preferably at least about 2% by weight, particularly preferably at least about 4% by weight). can be applied to crude IPA streams produced from propylene hydrate containing.

In practicing the invention, crude IPA is processed with added amounts of diisopropyl ether and water through sequential steps including multiphase separation. The process can be carried out in continuous or batch mode.

In particular, continuous implementation is preferred.

In the first step, the crude rp^ product is mixed with a diisopropyl ether-enriched stream that is recycled from the next point in the process during process step 6, described below. Furthermore,
The composition of the product mixture is as follows:
Optionally adjusted in the process to obtain a mixture containing approximately 73-83% by weight water.

Generally, addition of water is necessary to obtain a particular concentration. However, if the mixture of crude IPA and recycle stream contains enough water to bring its concentration in the mixture to a certain level, there is no need to add water. The mixture produced in this first step contains about 14-20% by weight of IP.
A preferably contains about 2-8% by weight diisopropyl ether and about 75-81% by weight water. Particularly preferred is a parsimonious mixture containing about 16-18% by weight IPA, about 4-5% by weight diisopropyl ether and about 77-79% by weight water. The remainder of the mixture, generally about 1% by weight, consists of polymer and/or sulfur-containing impurities, acetone, and possibly other impurities or by-products from the propylene aqueous phase reaction.

The water added to the crude IPA in the first process step of the present invention may be substantially pure water or alternatively
Water-rich process streams from sources in PA production or purification operations are highly suitable.

The distillation step in many common IPA purification processes produces a water-rich stream that is highly suitable for use in the present invention. The added water does not need to be of high purity, for example a certain amount of IPA
, isopropyl ether, polymers, etc.

In the second process step, the mixture from the first step is phase separated. This phase separation step is designated as the first phase separation to distinguish it from the second, subsequent phase separation that is part of the process. In the process of this first phase separation, isopropyl ether is concentrated in the upper phase, while water and I
PA is concentrated in the lower phase. Such a first phase separation occurs between the diisopropyl ether-rich first upper phase (non-polar) and the I
A separation is made between PA and a first lower phase (polar) rich in water.

The upper (non-polar) phase produced from this first phase separation step is rich in diisopropyl ether as well as polymer and sulfur-containing impurities. In the third process step, this upper phase is removed from the process. In fact, the present invention concentrates impurities in this phase, often ten times or more than the crude IPA provided in the present invention. If necessary, the removed upper phase is
Further processing, for example by conventional distillation or extractive distillation methods, can recover the IPA and diisopropyl ether from the removed upper phase. Processing the removed upper phase of a relatively small volume of first phase separation to remove impurities present in relatively high concentrations is more practical and economical than distillation of a substantially larger crude IPA stream.

The fourth step in the present invention is under the addition of isopropyl ether and the first phase separation step (second step of the whole process) (polar).
about 10-21% by weight IPA mixed with the phase, about 1-21% by weight IPA,
4% by weight diisopropyl ether and about 77-8
It consisted of obtaining a mixture containing 7% by weight of water. During this step, the diisopropyl ether added to the IPA-rich lower phase is preferably substantially free of polymer and sulfur-containing impurities. Although the particular source of added diisopropyl ether is not critical to the present invention, it is very convenient and common to recycle diisobutyl ether recovered from any purification process involving the entire purification step to this step. preferable. In the third step it is very convenient to recycle the purified ether from the crude ether taken from elsewhere in the invention or in the rpAf# production operation.

Following addition and mixing of diisopropyl ether to the lower phase of the first phase separation step, from the (second) lower phase to the (second)
) The product mixture is subjected to a second phase separation in a fifth process step to separate the lower phase. Also, as a case for the first phase separation step, the second upper phase is non-polar in character and rich in diisopropyl ether and polymer and sulfur-containing impurities, and the second lower phase is polar in character. , and enriched with IPA and water.

The separation of the two phases carried out for the purposes of the invention can in general be carried out suitably using a separation vessel of conventional design. In large-scale continuous processes, it can be carried out very conveniently, for example in horizontal cylindrical vessels with internal level control. In continuous operation, the phase separation vessel is preferably such that the liquid mixture has an average residence time of at least 10 minutes calculated for the gold ingot into the vessel in order to completely separate the phases. Long residence times can be used, ie at least about 20 minutes, especially at least about 40 minutes. Phase separations of 10 minutes or less can be carried out adequately, although at the expense of some process efficiency.

In the sixth step of the invention, the second upper phase is recycled for use in diluting the crude IPA in the first step as described above.

In the final seventh step of the process, the second lower phase resulting from the second phase separation is recovered as the desired purified IPA product.

The temperature and pressure conditions for the various process streams including rPA, diisopropyl ether, water and other components, and mixtures thereof need not be narrowly limited for the practice of this invention. Generally, the present invention is carried out at ambient or elevated temperatures, such as in the range of about 15-150°C.
In particular, rapid and complete phase separation can be obtained in the two phase separation steps by operating at temperatures in the range of about 50-110'C. However, highly effective phase separation can be achieved with long residence times and at relatively low temperatures.

In the two phase separation step, temperature is important to the performance of the process. Suitable process pressures include pressures high enough to maintain the process mixture in a substantially liquid state. Atmospheric pressure is quite suitable at low operating temperatures. Approximately 0
A process pressure in the range of 150 psi is quite suitable for preferred operation.

Following the implementation of the method of the invention, optionally purified IP
A can be processed to further purify it. This additional processing generally includes distillation, azeotropic distillation, solvent extraction and/or
Alternatively, it can be suitably carried out by conventional design and operation including extractive distillation. For example, IPA recovered from practicing the method of the invention may be extracted with an aqueous solvent to form water and IPA.
The diisopropyl ether overhead effluent can be further separated from the bottoms enriched with diisopropyl ether. An azeotropic aqueous IPA solution (approximately 87% by weight) is then obtained by distillation of the IPA/water mixture.
IPA) produces an overhead effluent and removes residual sulfur compounds and polymers. Dehydration of the IPA solution can be accomplished by azeotropic distillation in the presence of added diisopropyl ether. The resulting IPA/diisopropyl mixture can be distilled to produce a high grade IPA product.

Similarly, phase separation occurs in the second process step, and phase separation occurs in the third process step.
The diisopropyl ether-rich (non-polar) upper phase removed from the process in the process step can be treated by known procedures and techniques for the recovery and purification of diisopropyl ether and IPA valuable contents. Can be done. Conventional propylene processing ease is obtained by means of recovering and purifying the diisopropyl ether byproduct from the mixture resulting from the distillation involved in IPA purification.

When carried out together with conventional distillative and/or extractive separations, the present invention is advantageous in terms of producing products of increased quality. This is especially advantageous for producing low odor products suitable for use in cosmetics. By carrying out the process of the present invention in conjunction with conventional purification techniques, a low grade propylene feed can be processed to an acceptable grade IPA product. Generally, the lower the grade of the propylene feed, the higher the content of polymer and/or sulfur-containing impurities in the hydration process IP product produced from the feed. By providing means for purifying crude IPA independent of distillation and extractive distillation, the present invention can effectively improve the performance of new or existing IP^ purification facilitations.

Additionally, the method of the invention can be applied with fewer (or at least some) of the usual requirements for distillation and/or extraction of IPA; for example, in many distillation operations, the size and size of the distillation equipment can be reduced. The process of the present invention can be advantageously carried out with reduced energy requirements for evaporation and condensation of the effluent stream.

Next, the present invention will be described with reference to examples.

In order to implement this example, this example will be explained based on a flow sheet that is simply illustrated. In this example, the 1゛nIPA flow (
An example of the application of the continuous process according to the invention to the purification of 10 (indicated by 10 in the drawing) is shown. The crude rPA stream 10 contains 54.7% by weight IPA, 5.0
wt% diisopropyl ether.

It contained 0.2% by weight of polymer (ie, C9 and above) and sulfur-containing impurities, and 39.7% by weight of water. This crude IPA flow was u55 kg/hr (9
, 160 fb/hr). "Polymeric" compounds having C1 or higher carbon atoms were present at a level of about 8.2 kg Z hour (8 fb/hr) and sulfur-containing impurities at about 4.5 ppm (ppm calculated for elemental sulfur multiplied by 8). ) existed at the level of

In the first process step, stream 10 is
Crude rPA by mixing and diluting as stream 19 fed from an external source to the purification process containing water at (20,8071!, b/hr) and stream 37 recycled from the upper phase of the second phase separation zone. was diluted with water and isopropyl ether. Under steady state operation flow 37 is 77.6k
g/hour (171 fb/hour) of IPA, 132 kg/hour
It contained 290 i/hr of diisopropyl ether, traces of polymer, 4.1 kg/hr (9j2b/hr) of sulfur-containing impurities, and 30 kg/hr (67 f b/hr) of water. The purified diluted crude IPA stream 11 is then divided into 2
349 kg/hour (5,1791!,b/hour) ■fall,
339 kg/h (7471!, b/h) of isopropyl ether, 11392 kg/h (25,115
1 b/hr) of water, and 8.2 kg/hr (18ff
ib/hour) of polymer and sulfur-containing impurities.

Stream 11 (and all process streams downstream of 11) had a temperature of approximately 88°C (190@F). The process pressure is approximately 620 kP in stream 11, gauge (9
0 psig) to approximately 517 kP in the product stream 31
, gauge (75 psig).

(diluted phase IPA mixture 11 into a first phase portion N region, in this example a first upper phase 2 in a horizontal vessel 20 for continuous phase separation)
4 and the first lower phase 25. The size of vessel 20 was approximately 9081 (2,400 U, S, gallons) to provide an average residence time of approximately 1 hour, calculated based on the gold nuggets in stream 11. A first upper phase was continuously removed from vessel 20 and from the process as stream 26. Stream 26 contains about 95% sulfur found in the crude IPA and about 9
Approximately 8.03 kg/hour (17,7
fb/hr) of polymer/sulfur-containing impurities. In addition, stream 26 contains 277 kg/hr (611 fb/hr) of diisopropyl ether, 171 kg/hr (37 fb/hr)
6ffib/h) of IPA, 0.45 kg/h (l
fb/hr) of acetone and 66.2 kg/hr (146
f b/hr) of water.

A first lower phase was continuously removed as stream 21 from the first phase separation zone. This stream 21 weighs 2179 kg/hour (4,80
3 fb/hr) of IPA, 61.7 kg/hr (136 fb/hr)
b/h) of diisopropyl ether, 17 kg/h
hour (38ffib/hour) of acetone, 11325 k
g/hour (24,968j2b/hour) of water.

and 0.14 kg/h (0.31,b/h) of polymer and sulfur-containing impurities.

130 kg/hour (286I!b/hour) for the above flow 21
nearly pure isopropyl ether is introduced as stream 39 and the product mixture (stream 22) is passed through the second phase separation zone (
It was introduced into a container 30). This container 30 is 9080N
(2,400 U, S, gallons) and had an average residence time of about 1 hour, calculated based on the gold nuggets in stream 22. Phase separation in the second zone yields a diisopropyl ether-enriched second upper phase 32 which is continuously removed as stream 37 to dilute the crude IPA upstream of the first phase separation zone. Recirculated. flow 37
contained approximately 6.4 ppm of sulfur-containing compounds and trace amounts of polymer. Further, the phase separation in the second region resulted in a second lower phase 33, which was continuously removed from the container 30 as a stream 31. Stream 31 represents the (partially) purified rPA product of the process; this stream 31 has 2102k
g/hour (4,633 fb/hour) of IPA, 59°4k
g/hr (131 l b/hr) of diisopropyl ether, 1102 kg/hr (24,300 fb/hr) of water, and only about 0.14 kg/hr (0,31 b/hr) of polymer and 0.07 pp+m sulfur. It contained impurities.

In carrying out the process in this example of the method of the invention,
It was possible to reduce the content of diisopropyl ether and polymeric and sulfur-containing impurities in IPA very effectively. For the above impurity contents in crude IPA stream IO, the polymer was reduced to only about 1.5% by weight level and the sulfur was reduced to only about 5% by weight level.

The first treatment before and after treatment in this example according to the present invention.
The crude IPA flows were compared and the results are shown in Table 1 below.

- Table 1 flow 10 Flow 31 1 go 1 minute 1 1 fart 1 koha factory fart 1 pair ha IPA
5,008 2272 4,633
2102 Diisopropyl 456 207
131 59.4 Ether polymer 18 8.2 0.3
0.14 Sulfur compounds 0.041 0.019
0.0022 0.001 Acetone 39
17.7 37 16.8 Wednesday
3,639 1651 24,300 1
Determining the equilibrium phase distribution of the polymer components produced in the propylene hydration process in the two liquid phases obtained from the phase separation of a mixture containing water, IPA and diisopropyl ether in controlled proportions. For this purpose, a series of tests were conducted. The results of these tests indicate that crude TPA was
This shows that polymer impurities can be effectively removed from the stream.

Control tests (No. 0) show the analysis of representative crude IPA products for polymer impurities (all polymer analyzes given in these tests were obtained by GLC separation in a boiling point capillary column). ).

In test Nα1, a representative crude TP of 200mff1
was mixed with 440 ml of water in a stoppered cylinder and the mixture was placed in a constant temperature bath at a temperature of 30°C. After 5 minutes of phase separation, a sample of the lower (polar) phase was taken and analyzed for the content of polymeric impurities. Test this 5 minute separation Nα1
Shown as In the case of test N092, the same mixture was continuously phase separated for a further 225 minutes at 23°C. After continuous phase separation, the lower phase was analyzed for polymer impurity content.

In test Nα3, 200 ml of crude IPA was
Mix with 0ml water and heat the mixture at 60° for 5 minutes.
Phase separation occurred at C. In test Nα4, phase separation of this same mixture was continued for an additional 90 minutes at 40°C.

In each case a sample of the lower phase was taken to determine its polymer content.

The results of the test are shown in Table 2 in ppm of polymer impurities remaining in the rPA-rich (polar) lower phase resulting from phase separation.

0 (control) O-1831244107

[Brief explanation of drawings]

The accompanying drawings are flow sheets for implementing the method of the invention. 10, 11.19.21.22.26.31.37...
・Flow 20, 30... Container 24.32...
- Upper Minister 25, 33...Lower Minister Kunio Ogawa, Commissioner of the Patent Office 1. Display of the case 1985 Patent Application No. 320162 2, Title of the invention Process for purifying crude isopropyl alcohol 3, Person making the amendment Relationship to the case Patent applicant
・−Name Shell Oil Company ＋
,;,”＋・−fu4 agent

Claims (1)

[Scope of Claims] 1. A method for purifying crude isopropyl alcohol containing isopropylene alcohol, diisopropylene ether and water, comprising: (a) crude isopropyl alcohol as a recycle liquid from a subsequent process step (f); (b) in a first phase separation step, the mixture from step (a) is mixed with added water to obtain a mixture containing 73-83% by weight of water; (c) the first upper phase is removed from the process; (d) the first lower phase is added with diisopropylene. 10 to 10, based on the total weight of the product mixture, when mixed with ether.
obtaining a mixture containing 21% by weight of isopropyl alcohol, 1-4% by weight of diisopropyl ether and 77-87% by weight of water; (e) in a second phase separation step, converting the mixture from step (d) into diisopropyl ether; (f) mixing the second upper phase with crude isopropyl alcohol in step (a); and (f) mixing the second upper phase with crude isopropyl alcohol in step (a). A process for purifying crude isopropyl alcohol, characterized in that it is recycled as a recycle liquid and (g) a second lower phase is recovered as a purified isopropyl alcohol product.